Mechanical time fuse



Dec.21,1937. P GlRARD I MECHANICAL TIME FUSE Filed May l, 1936 NVENTOR PAUL, G/RARD7 BY @a Z/,Zegw

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Patented Dec. 21, 1937 FATE orifice MECHANICAL TIME FUSE Paul Girard, Lyon, France Application May 1, 1936, Serial No. 77,332 In France May 3, 1935 8 Claims.

This invention relates to clockwork operated time fuses for projectiles, and has for its object to provide-an improved and modied construction of the kind in which a firing pin is controlled by a rotary disc whose angular position can be regulated before ring, and which is'driven by the clockwork in a direction opposite to the direction of movement during regulation while the projectile is in flight.

According to the present invention a mechanical time fuse for projectiles is provided, comprising a spring-actuated firing pin, means for retaining said firing pin in set position, a safety pin adapted to lock said means at safety until the firing of the projectile, and two discs for controlling the means for retaining the firing pin in set position, said discs being adapted to be driven at different relative speeds upon the firing of the projectile and intheir rotation, after a period of time determined by the timing of the fuse, to arrive at a certain relative position in which they permit the means retaining the firing pin in set position to release said ring pin to cause the projectile to explode.

The invention Will readily be understood by reference to the accompanying drawing, which illustrates a constructional embodiment by way of example, and in which Figure 1 is an elevation in partial axial section, on an enlarged scale,

Figure 2 is a plan View in section on the line X-X of Figure 1,

Figure 3 is a section on line Y-Y of Figure 1,

Figure 4 is a section on line Z-Z of Figure 1,

"5 and Figure 5 is a vertical section of a portion of a shell showing the mounting of my fuse mechanism within the shell.

In the drawing I have only shown my timing mechanism, its position within the projectile being obvious to those skilled in the art. A designates a base adapted to be disposed within a shell (not shown). This base has a peripheral wall B, supporting an outer sleeve C, by a flange 4 5 D. Extending through the base A is a firing pin r slidingly mounted in a sleeve R. This pin is projected by a spring S, but is held in a retracted position by a latch. To this end the inner end of the pin r is notched at r', and the enlarged 5o inner end of the sleeve is also recessed, this recess extending or cutting through nearly a half of the sleeve-head and the pin as shown in Figure 4. The latch which engages in this notch will be later described. f

55 Extending across the upper end. 0f the wall B is a plate b, held in place by a-sleeve E. Extending through this plate s a shaft e, adapted to be driven by the driving spring of clockwork, not shown, but commonly used in mechanisms of this character. This shaft has a squared por- A:5 tion a. rlhis shaft passes freely through the center of a disc w', having a peripheral iange. Disposed within this liange is an internally toothed gear ring d having teeth m. Mounted on the squared portion of the shaft e, I0 and thus keyed thereto, is a sun pinion h, and disposed in intermeshing engagement with the pinion h and the internal gear d is a planet gear wheel c mounted on a shaft c' which is xed in and `extends downward from the wall m. The AjI5 lower end of this shaft c' may rest in a recess n which is formed in the disc w and extends nearly through a complete circle, as shown in Figure 2. I do not regard this as important however. o

Disposed below the disc w is a disc k having the same external diameter as disc w and rotating with the shaft e. VIt will be seen that by this vconstruction the disc lc and the sun pinion h will rotate in one direction at a certain speed `25 while the disc w and gear d will rotate in the opposite direction at a much slower speed.

Formed in the periphery of the disc lc is a notch or recess j, and formed in the wall of disc w' and ring dis a longer notch i having outward- 30 ly bevelled end walls. At some time in the rotation of the two discs w and 7c this notch will register, as shown'in Figure 2.

The firing pin latch is designated f. It is formed like a bell-crank lever and is pivotedV at Tg5 o. The long arm of the latch is normally' in engagement with the notch r in the firing pin ras shown in Figure 1. The other arm of the bellcrank lever f has at its end the upstanding semicircular pin p having its flat inner face confront- 40 ing the peripheries of the discs lc and w. If the latch lever f is permitted to have a clockwise rotation under the action of a spring t,'the'pin p will enter the notches z' and i, provided that the notches are in register. If the notches are in '45 register and the pin p can enter, then the long arm of the latch lever will be withdrawn from the notch 1" and the firing pin will be projected by its spring.

In order to prevent the latch from releasing the ring pin I provide an inertia-actuated safety pin g. This is slidably mounted in the base A and extends parallel to the firing pin. Its inner end is formed with a flange u, and the tail of the long arm of the latch is adapted to be disposed beneath this ange as shown in Figure 2. This safety pin prevents the long and heavy end of the latch lever from swinging outward and the short arm from moving inward and carrying its pin into contact with the peripheries of the discs k and w. The safety pin g has an exterior, relatively heavy head g and during the flight of the shell or upon the instant of its projection from the gun, the inertia of the safety pin will cause it to move to the dotted line position.

The operation of this fuse will be readily understood.

In initially setting the fuse, the notches i and 7 are brought into coincidence opposite thefmember p. The lever f has sufficient movement so that the member p under the action of spring t enters slightly into said notches, but the lever f is prevented from turning sufciently to release: the ring pin r, because of its other arm which abuts against the safety pin g. As the arm of the lever J` is engaged under the ange u of the safety pin g, it locks said pin y at safe position so as to prevent movement to the dotted line position in Figure 1.

In order to set and time the fuse, the driving spring (not shown) is tensioned by the driving shaft e, which is turned by hand with the aid of any suitable means not shown. The rotation of the shaft e causes the discs d and lc to turn in opposite directions and the pin p is forced out of the notches z' and j. This movement of the lever f causes the end of said lever abutting against the Vsafety pin g to move back clear of the flange u.

At the moment of firing, the-clockwork, which has just been wound, is set in movement by known means (not shown) and brings aboutthe inverse rotation of the shaft e. At the same instant the safety pin y is set back by inertia to the dotted line position. The lever f cannot, however, rock in the direction of the arrow a: under the action of the spring t andthe centrigual. force, (to thus move clear of the-recess q in the ring pin?" and so release said ringpin to cause the projectiler to explode), because the projecting member p now bears on the peripheries of therdiscs d, w and lc. Since' the discs' d, w and lc are rotating at different speeds and in opposite direction, the notches i and y will not coincide at the same point at each rotation, but after a period of time determined by the-timing, therecesses z' and y" again coincide opposite the projecting member p andthis mem'- ber enters these recesses by the action of spring t and centrifugal force and thus allows the lever f to turn about its pivot o clear of the recess q and thereby release the firing pin r.

It is to be observed thatI the lever f serves to effect a definite locking of the ring pin when the timing operation has not been carried out (which operation may be forgotten in the heat of the moment) by reason of' the fact that said lever f can not release the flange u of the pin g, so that an untimed projectile would have no other drawback than to act as a non-explosive projectile.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I d-eclare that what I claim is:-

1. A time fuse mechanism for projectiles including a spring-projected firing pin, means for retaining the firing pin from projection including a pivoted latch, a pair of independently rotatable discs, each having a notch in its periphery, clockwork actuated means operatively engaged with the two discs to rotate them in opposite directions andat relatively different speeds, the latch having a member adapted to enter the notches when they are in coincident register, the latch when its member enters the coincident notches releasing the ring pin and means urging said latch in a direction to cause the member to bear against the peripheries of the disks.

2. A time fuse mechanism for projectiles including a spring-projected firing pin, means for retaining the firing pin from projection including a pivoted latch, a pair of independently rotatable discs, each having a notch in its periphery, clockwork actuated means operatively engaged with the two discs to rotate them in opposite directions and at relatively different speeds, the latch having a member adapted to enter the notches when they are in coincident register, the latch when its member enters the coincident notches releasingthe ring pin, means urging said latch in a direction to cause the member to bear against the peripheries of the discs and an inertia shifted safety pin normally disposed in the path of movement of theY latch and preventing its movement into a firing-pin-releasing position; but shifted by inertia, upon projection of the projectile, out of its latch-impeding position.

3. A time fuse mechanism for projectiles including a spring-projected firing pin, means for retaining the firing pin from projection including a pivoted latch, a pair of independently rotatable discs, each having a notch in its periphery, clockwork actuated means operatively engaged with the two discs to rotate them in opposite directions ancl at relatively different speeds, the latch having a member adapted to enter the notches when they are in coincident register, the latch when its member enters the coincident notches releasing the ring pin, means urging said latch in a direction to cause the member to bear against the peripheries of the discs and an inertia shifted safety pin normally disposed in the path of movei ment of the latch and preventing its movement into a firing-pin releasing position; but shifted by inertia upon projection of the projectile out of its latch-impeding position, the safety pin having a flange preventing movement of the pin under inertia until the latch has been slightly withdrawn from the pin by the initial rotation of the discs.

4. A mechanical time fuse for projectiles including a spring projected firing pin, a latchlever engageable with the firing pin to hold it in retracted position, a pair of superposed discs each having a notch in its periphery, clockwork operated means for rotating the discs in opposite directions and at different speeds, a member on one end of the latch-lever adapted to bear against the peripheries of the discs and enter said notches when both notches are in coincident registration, and means urging the latch lever in a direction to cause its member to bear against the peripheries ofthe discs and enter the notches when coincident.

5. A mechanical time fuse for projectiles including a spring-projected firing pin, a latch lever engageable with the ring pin to hold it in retracted position, a pair of superposed discs each having a notch in its periphery, clockwork operated means for rotating the discs in opposite directions and at different speeds, a member on one end of the latch lever adapted to bear against the peripheries of the discs and enter said notches when both notches are in coincident registration, means urging the latch lever in a direction to cause its member to bear against the peripheries of the discs and enter the notches when coincident, and inertia retracted means preventing the iiring-pin-releasing movement of the latch lever until the projectile is fired. Y

6. A mechanical time fuse for projectiles including a spring-projected ring pin, a latch 'lever engageable with the firing pin to hold it in retracted position, a pair of superposed discs each having a notch in its periphery clockwork operated means for rotating the discs in opposite directions and at diierent speeds, a member on one end of the latch lever adapted to bear against the peripheries of the discs and enter said notches when both notches are in coincident registration, means urging the latch lever in a direction to cause its member to bear against the peripheries of the discs and enter the notches when coincident, inertia retracted means preventing the firing-pin-releasing movement of the latch lever until the projectile is red and means locking the said inertia-retractable means against latch-releasing movement until said discs have rotated from an initial position.

7. A mechanical time fuse for projectiles comprising a spring-projected firing pin, means for retaining said ring pin in retracted position, a

safetypin adapted to lock said means at safety until the ring of the projectile and two discs for controlling the means for retaining the firing pin in set position, said discs being adapted to be driven at different relative speeds by a clockwork mechanism upon the firing of the projectile and in their rotation, after a period of time determined by the timing of the fuse, to arrive at a certain relative position in which they permit the means retaining the iiring pin in set position to release said ring pin to cause the projectile to explode. Y

8. A mechanically operated time fuse including a ring pin, a latch holding the ring pin retracted, means urging the latch out of engagement with the ring pin, and a plurality of differentially movable timing elements each having thereon an opening permitting the retraction of the latch, said elements, when the openings are in coincident holding the latch from disengagement from the firing pin but permitting the retraction of the latch when the openings are coincident and motor driven means for moving the elements into said coincident position. Y

PAUL GIRARD. 

